Heavy molecuels are concentrated near Saturn's equator, which suggests they came from the planet's rings. Credit: NASA / JPL-Caltech/Space Science Institute
What they saw: Before Cassini (rest in peace) plummeted into Saturn last month, the spacecraft made several dives through the planet's outer atmosphere. A mass spectrometer on board detected large, complex molecules in the planet's atmosphere — including methane, carbon dioxide and more complex molecules, reports Alexandra Witze for Nature. The researchers believe the particles came from the rings because they were most common around the planet's equator and high altitudes.
Why it matters: The voyage allowed them to test long-standing hypotheses about the composition of Saturn's atmosphere. By studying planets in the outer solar system, we can learn more about how our corner of the cosmos formed.